Mobile advertising is forecast to be the most important driver of the global advertising economy over the next three years, accounting for more than a third of the $90bn in new revenue expected by 2016.

Advertising delivered to smartphones and tablets will account for 36% of new global ad spend over the next three years, according to a new forecast by global media buying agency group ZenithOptimedia.

However, the growth in mobile advertising will be in addition to rather than at the expense of traditional media such as TV and newspapers, according to ZenithOptimedia.

The rise of mobile advertising is in stark contrast to the upheaval caused by the rise of PC and laptop-based internet display and search advertising in the past decade, dominated by Google, which has hit the press industry particularly hard.

"This is the first time in the past 20 years that a new platform is expanding overall media consumption without cannibalising any of the other media platforms," says Jonathan Barnard, head of forecasting at ZenithOptimedia, which published a three-year global forecast on Monday.

By 2016 mobile advertising will become the fourth-largest medium globally, worth $45bn, leapfrogging radio ($37bn), cinema ($34bn) and outdoor ($40bn).

The global ad market is forecast to be worth $500bn this year – with 5.3% growth expected in 2014 and almost 6% in 2015 and 2016 – with mobile driving what Zenith says will be the strongest period of growth in a decade. By 2016 the global ad market will be worth almost $590bn.

"The principle engine of this growth will be mobile technology," says Barnard.

Over the next three years TV advertising will be the second biggest contributor to the $90bn growth in global ad spend, accounting for 34% of the new money.

Desktop advertising on PCs and laptops will be third accounting for 25%.

By 2016 TV advertising will remain by far the biggest medium with a 39% share in 2016 valued at $230bn. TV's share of global ad spend will peak this year at 40%.

By 2016 desktop internet advertising will be the world's second largest medium, accounting for 19% at $111bn, and newspaper advertising will rank third at $82bn and a 14% share.

Overall ZenithOptimedia's global forecast is bullish, upgrading a September prediction of 5.1% growth in 2014 to 5.3%.

This is in contrast to WPP's media buying arm Group M, which has also published a new global forecast but has taken a more pessimistic view of next year.

Group M has downgraded a previous 5.1% growth forecast for 2014 to 4.6%, blaming "economic gridlock in the US and a persistent financial crisis in the Eurozone".

Adam Smith, Group M's futures director, said that worldwide there are plenty of examples of "local, specific support for ad spend growth" but that "total global spending remains vulnerable to a wider economic downslide".

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